Sweet corn is a warm-season vegetable that can be grown easily in any garden with sufficient light, fertility, growing season and space. It is especially popular with home gardeners because it tastes appreciably better when it is harvested and eaten fresh from the garden. Successive plantings can yield continual harvests from early summer until frost if the weather cooperates.
Sugary enhancer hybrids contain the sugary enhancer (SE) gene, that significantly raises the sugar content above standard SUs while retaining the tenderness and creamy texture of standard varieties. The taste, tenderness and texture are outstanding. SEs are the gourmet corns of choice for home gardeners because they contain the best qualities of both SU and Sh2 types. Fresh from the garden, virtually all current SE releases have eating quality that is superior to all other types. No isolation from standard SUs is necessary.
When to Plant
Sweet corn requires warm soil for germination (above 55°F for standard sweet corn varieties and about 65°F for supersweet varieties). Early plantings of standard sweet corn should be made at, or just before, the mean frost-free date unless you use special soil-warming protection such as clear polyethylene mulch film.
For a continuous supply of sweet corn throughout the summer, plant an early variety, a second early variety and a main-crop variety in the first planting. Make a second planting and successive plantings of your favorite main-crop or late variety when three to four leaves have appeared on the seedlings in the previous planting. Plantings can be made as late as the first week of July in most areas.
Spacing & Depth
Plant the kernels (seeds) 1/2 inch deep in cool, moist soils and 1 to 1 1/2 inches deep in warm, dry soils. Space the kernels 9 to 12 inches apart in the row. Plant two or more rows of each variety side by side to ensure good pollination and ear development. Allow 30 to 36 inches between rows. All sweet corns should be protected from possible cross-pollination by other types of corn (field, pop or flint). If you plant supersweet or synergistic sweet corn varieties, plan your garden arrangement and planting schedule so as to prevent cross-pollination between these varieties and with any other corn, including nonSh2 sweet corns. Supersweet varieties pollinated by standard sweet corn, popcorn or field corn do not develop a high sugar content and are starchy. Cross-pollination between yellow and white sweet corn varieties of the same type affects only the appearance of the white corn, not the eating quality.
Cultivate shallowly to control weeds. Chemical herbicides are not recommended for home gardens. Although corn is a warm-weather crop, lack of water at critical periods can seriously reduce quality and yield. If rainfall is deficient, irrigate thoroughly during emergence of the tassels, silking and maturation of the ears. Hot, droughty conditions during pollination result in missing kernels, small ears and poor development of the tips of the ears. Some sweet corn varieties produce more side shoots or "suckers" than others. Removing these side shoots is time consuming and does not improve yields.
Each cornstalk should produce at least one large ear. Under good growing conditions (correct spacing; freedom from weeds, insects and disease; and adequate moisture and fertility), many varieties produce a second ear. This second ear is usually smaller and develops later than the first ear. Sweet corn ears should be picked during the "milk stage" when the kernels are fully formed but not fully mature. This stage occurs about 20 days after the appearance of the first silk strands. The kernels are smooth and plump and the juice in the kernel appears milky when punctured with a thumbnail. Sweet corn remains in the milk stage less than a week. As harvest time approaches, check frequently to make sure that the kernels do not become too mature and doughy. Other signs that indicate when the corn is ready for harvest are drying and browning of the silks, fullness of the tip kernels and firmness of the unhusked ears. To harvest, snap off the ears by hand with a quick, firm, downward push, twist and pull. The ears should be eaten, processed or refrigerated as soon as possible. At summer temperatures, the sugar in sweet corn quickly decreases and the starch increases. Cut or pull out the cornstalks immediately after harvest and put them in a compost pile. Cut the stalks in one foot lengths or shred them to hasten decay.
Corn earworms are a problem in sweet corn every year. Earlier plantings are not badly infested in areas where the pest does not overwinter, but later harvests usually have severe earworm damage unless timely control measures are followed. Corn earworms deposit eggs on the developing silks or on the leaves near the ear. The tiny caterpillars follow the silks down into the ear, where they feed on the tip. Only one corn earworm will be found per ear because the caterpillars are cannibalistic, with the largest devouring any others present. Once the worm is inside the protective husk covering, there is no effective control. Anything that restricts the worm-such as tightening the tip of the husk with a rubber band or clothespin after the silk appears, or inserting mineral oil (1/2 medicine dropperful) in the silk tube-helps to decrease the damage.
Corn rootworm beetles may cause extensive silk damage that interferes with pollination. Later plantings usually suffer the greatest damage, especially where field corn is grown. Beetles multiply in early plantings of field corn, mature and migrate to plantings of young, tender sweet corn. Silk and the young, tender, green leaves are preferred feeding sites. If infestation is sufficient to remove silk before pollination, cobs develop without a full set of kernels. Control measures must be taken as the silk emerges.
European corn borers damage stalks, tassels and ears. As their name indicates, corn borers bore into the plant; and the stalks break over when damage is severe. Corn borers also may bore into the cob and be found after cooking. A suggested insecticide can be applied at 5 day intervals, beginning when eggs hatch in June. Spray applications for earworms usually give adequate control of corn borers.
Flea beetles often attack early in the spring as the corn plants emerge through the soil. Flea beetles can be quite damaging when numerous and they may carry Stewart's bacterial wilt disease. Stewart's wilt is a bacterial disease spread by the flea beetle. This disease causes yellow streaks in the leaves, stunting and death of young plants of susceptible varieties. The disease occurs more frequently in the southern states and is not severe after cold winters or when resistant varieties are planted. If possible, plant varieties with good resistance.
Smut is caused by a fungus that invades the kernels. It develops as a swollen black pustule (gall) in the ear and sometimes infects the tassel. Some sweet corn varieties are more tolerant to smut than others. Smut occurs most frequently on white varieties and is often severe when extremely dry or hot weather occurs just before and during tasseling. Remove and destroy smut galls while they are moist and firm. Do not discard these galls in or near the garden. Place in the garbage or burn them. The smut is not poisonous, but it is unpleasant to handle. Break off the infected part of the ear. The remainder is suitable for eating. The immature smut fungus or "maize mushroom" is highly prized in Mexican cooking. Harvest when the fungus is expanded, but before it becomes black and dried out. The time generally is about 2 to 3 days before the sweet corn reaches peak eating quality.
Questions & Answers
Q. How long does it take sweet corn to develop from the first appearance of silks to harvest?
A. About 5 days are required for complete pollination after the first silks appear. Harvest begins about 20 days after first silking.
Q. The germination of my Sweet corn is low. How can I get a better stand?
A. The seeds of supersweet varieties are shrunken and do not germinate readily in cold, wet soil. Do not plant too early in the spring. Wait until the soil is warm, preferably 65°F. Sow the seed more thickly and thin if necessary. Fungicide seed treatments may also be helpful.
Q. Why don't my sweet corn ears fill out to the tips?
A. Several conditions can cause poor kernel development at the tip of the ear such as dry weather during silking and pollination; planting too close; poor fertility, lack of potassium; and poor natural pollination. These conditions may be overcome by watering in dry weather; planting at recommended spacing (9 to 12 inches in the row); proper fertilization; and planting short rows in blocks of two or more for more complete pollination.
Q. What is the best way to grow early corn?
A. Choose an early maturing variety, plant early and shallowly (about 1/2 inch deep), and cover the row with clear polyethylene film. Use 1 or 2 mil film 3 feet wide and cover the edges and ends to warm the soil around the seeds. The small plants can be left under the plastic for 2 to 4 weeks. Remove the film, or cut slits and carefully pull the plants through before the weather becomes too hot. It is wise to experiment with this technique on a small scale first. Unseasonable heat can quickly cook and kill young seedlings under clear plastic.
Q. How can I keep raccoons out of my sweet corn?
A. It is virtually impossible to keep raccoons out of garden, although many methods are employed. The most successful seems to be an electric fence made with two wires, one about 4 inches above ground level and the other at 12 inches. The fence must be operating well in advance of the time that the corn approaches maturity. Raccoons prefer to eat sweet corn in the early milk stage, just before it is ready to harvest.
Selection & Storage
Corn is a European word meaning kernel, the corn plant itself is native American in origin. It is greedy for soil nutrients, prone to weeds and disease, destroyed by small animals, wind and frost. So why do we go through all the trouble of growing corn? Because no corn is as fresh and sweet as the corn you grow yourself. The period of peak freshness for sweet corn is measured in minutes not hours or days. The best corn is simply the freshest corn. Proper timing for harvest is crucial to the quality of sweet corn.
Harvest sweet corn when the ears are full and blunt at the tip. The husks should be tightly folded and green. Using your thumb nail, poke an end kernel. It should squirt forth milky white sap. Underripe corn will contain a watery liquid; overripe corn will have a tough skinned kernel with doughy interiors. Also look at the silk, it should be turning brown and dry on the end. Storing sweet corn for long periods of time will destroy it. The sugar quickly turns to starch, losing flavor, quality and most of all sweetness. If you must store sweet corn, use perforated plastic bags and get it into the refrigerator as soon as possible. Warm temperatures hasten the conversion process. Try to use the corn within 1 to 2 days and do not husk until just prior to cooking.
Nutritional Value & Health Benefits
Sweet corn is high in fiber, niacin, folate and some vitamin A. Folate has been found to prevent neural-tube birth defects and current research suggests that it helps to reduce the risk of heart disease and stroke. Fiber, of course, helps to keep the intestinal track running smoothly.
Nutrition Facts (Serving size: 1 ear yellow sweet corn )
Protein 2.56 grams
Carbohydrates 19.3 grams
Dietary Fiber 2.15 grams
Potassium 191.73 mg
Vitamin A 167 IU
Niacin 1.24 mg
Folate 35.73 mcg
Preparation & Serving
Traditionally, boiling is the way to prepare corn on the cob. However, it can be steamed, grilled, roasted, and even microwaved. When boiling sweet corn, do not add salt to the boiling water as it only serves to toughen the kernels as does overcooking. To shuck corn, pull the husks down the ear and snap off the stem at the base. Under cold running water, rub the ear in a circular motion to remove the silk or use a stiff vegetable brush. To remove corn from the cob, you will need a sharp paring knife. Place the shucked ear on a plate, large end down. Starting at the tip of the ear, run the knife straight down to the stem end leaving about 1/4 inch of the kernel on the cob. This prevents cutting off the tough cob fibers. Rotate the ear and cut until all the kernels have been removed. Now, using the back of the knife, gently scrape down the entire cob to remove the milk left behind.
Freezing is the best method for preserving the quality of sweet corn. Although it cans fairly well, it must be processed in a pressure canner for extremely long periods of time. Corn can also be pickled into corn relish. To Freeze Sweet Corn Select only tender, freshly gathered corn in the milk stage. Husk and trim the ears, remove silks and wash in cold water.
Corn on the cob
Water blanch small ears (1 1/4 inches or less in diameter) 7 minutes, medium ears (1-1/2 inches in diameter or more) 9 minutes. Cool in an ice water bath for approximately the same amount of time as blanching. Cool completely to prevent a "cobby" taste.
Drain and package in gallon-size zip closure freezer bags. Push excess air from the bags, seal and freeze. Leave space between each bag until frozen.
Whole Kernel Corn Water blanch corn on the cob for 4 minutes. Cool promptly in ice water for 4 minutes. Drain and cut corn from the cob. Cut kernels from the cob about two-thirds the depth of the kernels. Package in zip closure freezer bags or rigid containers leaving 1/2 inch head space.
Smothering corn with butter and salt is the traditional way of serving corn on the cob. Instead, try squeezing on fresh lemon or lime juice or brush with olive oil and sprinkle on your favorite dried herb blend. Fresh herbs, dried herbs and spices used to enhance the flavor of corn include thyme, paprika, chives, lemon balm and chervil. Garlic powder also creates a nice flavor boost as well as freshly ground black pepper.
Boiled Corn on the Cob
Drop shucked, washed, corn into a pot of rapidly boiling water. Boil for 4 minutes. The cooking time will vary depending on the size and age of the corn. Do not over cook the corn or it will toughen. Remove an ear and taste; it should still be slightly crisp. Serve with herbs, lime juice or butter and salt and black pepper.
Dried Herb Blend (for corn and other vegetables)
4 tablespoons paprika
1 teaspoon cayenne pepper
1 tablespoon black pepper
1 tablespoon garlic powder
1 tablespoon salt
1 teaspoon thyme
Combine all ingredients and pour into a shaker. Use on any vegetable instead of salt.
Crusty Skillet Corn
2 tablespoons canola oil
8 medium ears of corn (kernels cut and scraped from the cob)
1/2 teaspoon salt
1/2 cup flour
1. Heat an 8-inch cast iron skillet in a 425 degree oven for about 20 minutes.
2. Meanwhile, remove the corn from the cob. Place in a large bowl. Add the salt and flour to form a thick batter-like mass. All of the flour should be moist. If the corn is not fresh, you may need to add a few sprinkles of water.
3. Carefully remove the skillet from the oven and pour the oil into the skillet. Rotate the skillet so that the oil covers the entire surface.
4. Quickly scrape the corn mixture into the hot skillet. Press the batter into place with a spoon, do not stir.
5. Bake until a nice crust forms on the top and it starts to brown about 20 minutes depending on sweetness of the corn.
6. Remove and invert onto a serving plate. If it is not brown, return to the hot oven for a few more minutes. Cut into 4 wedges. The corn will be rather crumbly, so use a spatula to serve. Serves 4.